Skip to content
Go to file

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time

VMFest is a PalletOps project to turn VirtualBox into a light-weight cloud provider. This is very useful for when developing cloud automation. VirtualBox's Virtual Machines (VMs) boot very quickly (seconds), so why not take advantage of it?

VMFest takes the form of a library, and you can use it as a toolkit to create your own virtualization environments.

This project is work in progress, so feedback and suggestions are welcome. Please use the issues for this purpose.

Release Notes

Can be found here.


NOTE: VMFest 0.3.0 added support for XPCOM-based communication with VirtualBox. Using XPCOM only works when VMFest and VirtualBox are in the same machine, but it is the easiest setup, and also generally faster. VMFest still supports WebServices communication, which is what VMFest version 0.2.6 and older supported, and this support is still needed for when VMFest and VirtualBox are on separate machines. The instructions below are for using the new XPCOM communication subsystem, and hence, are shorter :). You can still find how to setup the webservices communication at the end of this page.

WARNING: the java/XPCOM bridge is broken for Debian Weezy and Ubuntu 12.x (see ticket #11232 for more details. You'll get a nice segmentation fault in those cases. In these cases, please revert to the WebServices configuration listed at the end of this page.

Install VirtualBox 4.3.x

Download and install VirtualBox 4.3.x. VMFest 0.4.x won't work with any older version.

For VirtualBox 4.2.x, use VMFest 0.3.x

Setup VMFest in your project

The following instructions are for setting up Leiningen project, just because pretty much everyone using Clojure uses lein, but sticking vmfest in your classpath will suffice.

Add the following dependencies to your project.clj:

   [vmfest "0.4.0-alpha.1"]
   [org.clojars.tbatchelli/vboxjxpcom "4.3.4"]

and tell VMFest where VirtualBox is installed. In OSX this would be:

   :jvm-opts ["-Dvbox.home=/Applications/"]

and for Ubuntu/Debian this would be:

 :jvm-opts ["-Dvbox.home=/usr/lib/virtualbox"]

Basic Features

Create VMs programmatically

VMFest has a data oriented API to create VMs. There are two data structures needed to create a VM: one describing the hardware and the other one describing the image that the VM will boot off.

Hardware specs

You can define every hardware aspect of a VM as a hash map. Consider this map:

   {:memory-size 512
    :cpu-count 1
    :network [{:attachment-type :host-only
               :host-only-interface "vboxnet0"}
              {:attachment-type :nat}]
    :storage [{:name "IDE Controller"
               :bus :ide
               :devices [nil nil {:device-type :dvd} nil]}]
    :boot-mount-point ["IDE Controller" 0]}}

This map describes a VM with 1 CPU, 512MB RAM, two network interfaces plugged in: one attached to VirtualBox's host-only network named "vboxnet0", and another one attached to NAT. For storage it has an IDE controller in the first slot. The first channel in this IDE controller and the second channel has a DVD attached to the master. Finally, a the booting image (will cover this later) will be attached in the master slot master in the channel 1 of the IDE.

Image specs

You can use any VirtualBox image with VMFest, but we encourage using immutable ones, a must if you want to use VMFest as a cloud provider.

VMFest lets you provide image metadata that will be passed on to the libraries using VMFest. This image metadata can contain information like the user/password for the image, the OS family, 32 or 64 bits, etc., but for now we only care about one piece of data: the image location in the file system --which for historical reasons it is called uuid:


Create VMs from specs

A new VM is created from a hardware spec and an image spec. The following will create a VM on the VirtualBox host defined by my-server.

(require '[vmfest.manager :refer [instance]])
(def my-machine 
     (instance my-server "my-vmfest-vm" 
        {:uuid "/Users/tbatchelli/imgs/vmfest-Debian-"}  
        {:memory-size 512
         :cpu-count 1
         :network [{:attachment-type :host-only
                    :host-only-interface "vboxnet0"}
                   {:attachment-type :nat}]
         :storage [{:name "IDE Controller"
                    :bus :ide
                    :devices [nil nil {:device-type :dvd} nil]}]
         :boot-mount-point ["IDE Controller" 0]}))

Manage VMs

You can start, pause, resume, stop, power-down and destroy (careful with destroy if you are not using immutable images!). It shouldn't be too hard to figure out what they do. The only operation that needs some explanation is destroy, as it will remove the VM and also the attached image if it is not immutable.

Each of these functions take a machine as argument, e.g.:

(start my-machine)
(pause my-machine)
(resume my-machine)
(stop my-machine)
(destroy my-machine)

Operating on existing machines is also possible:

(def my-machine (find-machine my-server "a-machine"))
(start my-machine)

Finally, you can get the IP address of your VMs, provided that the images the VMs are running have VirtualBox Guest Additions installed:

(get-ip my-machine)

Cloudy features


The main use case that we had when we built VMFest was to use VirtualBox like a lightweight cloud provider.

Most cloud providers will typically provide a set of images and a set hardware profiles, and when you want to create a new instance (VM) you select a profile for each, e.g., ubuntu 10.04 + Large Machine.

To emulate this convention, vmfest has these two concepts: Image Models and Hardware Models. These are lists of named specs, both for image and hardware. These specs are built with the clojure maps described above, and you can add your own too.

When creating a new VM, you can reference these specs by key instead of passing the specs. For example, in my laptop, I can instantiate the exact same VM as above with:

(instance my-server "my-vmfest-vm" :debian- :micro)

Setting up VMFest Image Models

We have created a few images to be used with VMFest. Although VMFest can operate on any image, we want to build high quality images that every one can confidently use. We also provide a way to setup those images on your local VMFest setup.

(setup-model "" my-server)

This will download and install this image as immutable. From there on you can start using it as :debian-

Using Vagrant Boxes as Image Models

NOTE: this feature is Alpha.

VMFest can use any well configured Vagrant box as an image model. To do so, will setup the image similarly as above, but passing some extra parameters, e.g.:

(setup-model "" my-server
   :meta {:os-family :ubuntu :os-version "10.04" :os-64-bit true})

Once installed, the Vagrant box can be used just as any other VMFest model.

Fast VM Instantiation

VirtualBox provides a way to run many VMs out of the same disk image. This is done using immutable disk images. When a image is set as immutable, every time you attach new VM to this disk, VirtualBox creates a differencing disk. This differencing disk contains the disk sectors from the original disk that have changed, or the difference. Each VM attached to an immutable image can diverge independently once it is booted.

The benefit of using immutable images this way is that in order to start two or more VMs out of the same exact disk image, you don't have to create one copy the original disk image for each VM. This results in big savings in terms of time and most importantly, space.

When you use VMFest then, you can create as many VMs as you please and attach them to the same image. This is usually a very fast operation, typically sub-second. Here is one example of how to do this:

;; create some names for the VMs
(def names ["slave-1" "slave-2" ... "slave-N" "master"])

;; instantiate the VMs
(def machines 
     (map (fn [name] 
              (instance my-server % :debian- :micro))
;; start all the VMs
(map start machines)

Low Level API

There is a low-level API to program VirtualBox from Clojure. This API eliminates some of the complexity of connecting to VirtualBox, but we'll leave this explanation for another day. Just know that it's there, and you can look at the manager.clj sources and the tests to see what this API is about.


We've created a playground project for you to test VMFest. You can find the tutorial here.

(use 'vmfest.manager)
(use '[vmfest.virtualbox.image :only [setup-model]])

;; First we need to define a connection to our VirtualBox host
;; service.
(def my-server (server))

;; We need an image model to play with. This will set up a fairly up-to-date
;; Debian image.
(setup-model "" my-server)
;; {:image-file "/var/folders...}

;; let's check that the image model has been installed
;; (:debian- <-- you should see this

;; Time do create a VM instance. We'll call it my-vmfest-vm. This is
;; the name that will appear in VirtualBox's GUI.
(def my-machine (instance my-server "my-vmfest-vm" :debian- :micro))

;; Notice that once we have created a VM we don't need to reference
;; the server anymore
(start my-machine)

;; Get the IP address of the machine. At this point, you can SSH into
;; this machine with user/password: vmfest/vmfest
(get-ip my-machine)

;; You can pause and resume the VM.
(pause my-machine)
(resume my-machine)

;; Stopping the VM will send a signal to the OS to shutdown. This will
;; not the VM itself, just the OS run by the VM
(stop my-machine)

;; This will turn off the VM completely and immediately.
(power-down my-machine)

;; Once we are done with this VM, we can destroy it, which will remove
;; any trace of it's existence. Your data will be lost, but not the
;; original image this VM was booted off.
(destroy my-machine)


;; Now we are going to create multiple instances of the same image.
;; First we need some names for each instance. names will do just
;; that, e.g.: (names 3) -> ("vmfest-0" "vmfest-1" "vmfest-2").
  names [n]
  (map #(format "vmfest-%s" %) (range n)))

;; This function will create a debian instance based on the image
;; downloaded above
(defn deb-instance [server name]
  (instance server name :debian- :micro))

;; Let's create a few images. Notice that in this case we're creating
;; 5. Each machine takes roughly 0.5GB of RAM, so change the number to
;; match your available RAM.
(def my-machines (pmap #(deb-instance my-server %)
                       (names 5)))

;; From here we can start, power-down, and destroy all the VMs in parallel.
(pmap start my-machines)
(pmap power-down my-machines)
(pmap destroy my-machines)

Connecting to VirtualBox via WebServices

Replace the vboxjxpcom dependency in project.clj with this one:

   [org.clojars.tbatchelli/vboxjws "4.3.4"]

Start the VirtualBox server (vboxwebsrv) by issuing the following on the shell:

$ vboxwebsrv -t0

Finally, disable login authorization in VirtualBox server (you'll only need to do it this one time):

$ VBoxManage setproperty websrvauthlibrary null


If you need help setting up or programming VMFest, or have suggestions, or just want to chat, here are your options:


Copyright © 2013 Antoni Batchelli and Hugo Duncan

Distributed under the Eclipse Public License, the same as Clojure.


manage your local VMs from the repl



No packages published
You can’t perform that action at this time.